Reversing mechanism for engines



' H. B. PETERSON, JR 2,376,182

REVERSING MECHANISM FOR ENGINES May 15, 1945.

Filed March 23, 1943 through port 34 to chamber 20 and exhaust passage 26 therebyto increase the speed with which spring 15 can lift sleeve 2. On the other hand, when fluid pressure is admitted from tank l9 to chamber 20 to restore contact of roller 1 with the cam, fluid pressure will flow not only upwardly past check valve 23 but also rapidly through port 34 until this latter port is covered by spool 33. This insures rapid restoration of contact of the follower roller with the newly selected set of cams.

The foregoing structure and mode of operation will not interfere in any way with the valve tappet clearance take up operation During the take up operation, if valve tappet clearance should develop the constant upwardly biasing force of spring II will push plunger l3 and valve rod 8 upwardly to take up the clearance, and this will be accompanied by fiow of fluid from chambers 20 and 22 upwardly past check valve 23 to become trapped beneath plunger Hi. This trapped fluid cannot escape downwardly past the check valve and thus the equivalent of a solid link is created from roller I through bod l4 and thence to the trapped fluid beneath plunger 13 to operate push rod 8. This operation is well known in the art as is also the fact that the spring H exerts a force far less than the force of the usual valve spring.

As a result of my improved structure and mode of operation, it is seen that the cam follower roller may be lifted'rapidly and positively and yet be controlled with a high degree of precision through operation of piston 27 and its pin 29. The structure for accomplishing this improved result is relatively simple and compact and economical in construction, operation and maintenance with no additional moving parts other than what are already embodied in said Essl invention. Any tendency towards leakage upwardly past plunger [3 is immediately accompanied by admission of compensating fluid upwardly past check valve 23. As a result of being able to compensate for such leakage, it is seen that the use of a port such as 34 does not in any way limit the effectiveness of the device for taking up valve tappet clearance.

It will of course be understood that various changes in details of construction and arrangement of parts may be made by those skilled in the art without departing from the spirit of the invention as set forth in the appended claims.

I claim:

1. A control device for a reversing mechanism for internal combustion engines of the type having a valve selectively operated by forward or reverse sets of cams on a camshaft which is axially shiftable to bring either set of cams into operation comprising, in combination, a push rod structure adapted to be operated by one or the other of said sets of cams, means for collapsing said push rod structure so as to move a portion thereof out of operative relation to said cams thereby allowing said camshaft to be shifted axially to bring either set of cams into operative relation with the push rod structure, and means for accelerating the rate of collapse of said push rod structure automatically in response to initial operation of said collapsing means.

2. A control device for a reversing mechanism for internal combustion engines of the type having a valve selectively operated by forward or reverse sets of cams on a camshaft which is axially shiftable to bring either set of cams into operation comprising, in combination, a push rod structure adapted to be operated by one or the other of said sets of cams, hydraulically controlled means for collapsing said push rod structure so as to allow said camshaft to be shifted axially to bring one or the other of said sets of cams into operative relation to said push rod structure, and auxiliary means controlled by said hydraulically controlled means for automatically accelerating the collapse of said push rod structure after initial operation of said hydraulic means.

3. The combination in a control device for a reversing device for collapsing a push rod structure of an internal combustion engine comprising, a cam follower sleeve having a cam follower at its lower end, a push rod seat slidably supported on the upper end of said sleeve, a bore located internally of said sleeve, a plunger disposed within said bore for relatively moving said push rod seat and cam follower away from each other, means for moving said sleeve in a direction toward said seat thereby to collapse the push rod structure, means for supplying and controlling pressure fluid to said bore for determining said relative movement between the sleeve and push rod and for exhausting fluid from said bore to effect collapse of the push rod structure, and an auxiliary port normally closed by said plunger and adapted to be opened upon initial collapsing movement of the plunger so as to discharge fluid from said bor to accelerate said collapsing movement.

4. The combination in a control device for a reversing device for collapsing a push rod structure of an internal combustion engine comprising, a cam follower sleeve having a cam follower at its lower end, a push rod seat slidably supported on the upper end of said sleeve, a bore located internally of said sleeve, a plunger disposed within said bore, means including a check valve for supplying pressure fluid to said bore for relatively moving said plunger and bore to maintain the cam follower in its normal operative position, fluid pressure-controlled piston for unseating said check valve to allow discharge of fluid from said sleeve to effect initial collapse of the push rod structure, a port in said sleeve normally closed by said plunger but adapted to be open upon initial collapsing of the push rod structure, and means allowing communication between said port and bore after said port is open thereby to increase the rate of discharge of fluid from said cylinder and accordingly accelerate the collapsing of the push rod structure.

5. A control device for a reversing mechanism for internal combustion engines of the type having a valve selectively operated by forward or reverse sets of cams on a camshaft which is axially shiftable to bring either set of cams into operation comprising, in combination, a push rod structure adapted to be operated by one or the other of said sets of cams, means for collapsing said push rod structure so as to move a portion thereof out of operative relation to said cams thereby allowing said camshaft to be shifted axially to bring either set of cams into alignment with the push rod structure and thereafter for restoring the push rod structure to its operative relation with the new cam, and means for accelcrating the rate of restoration of said push rod structure automatically in response to initial HARRY B. PETERSON, JR. 

